Fig. 1: Design and working principle of the RNA-fueled DNA origami engine.

A Schematic of the 6-helix bundle DNA origami (6 HB, ~410 nm) and AFM image of the 6HB (scale bar: 400 nm). B Schematic of the engine structure composed of four 6HB DNA origami rods. The first and second rods are connected via two ssDNA hinges that provide mechanical flexibility and elastic restoring force, while the second–third-forth rods are rigidly connected via six dsDNA bridges (Supplementary Fig. 2). The RNA-fueled switching module is located at the junction of the first and second 6HB. Close-up schematic of the hinge region: two sticky ends on the first and second 6HB hybridize with an RNA linker to form a U-shaped structure, maintaining the engine in a folded state. RNase H specifically recognizes and cleaves the DNA/RNA duplex, releasing the constraint and allowing the hinge to open. AFM image of the unfolded and folded conformation of the engine (scale bar: 400 nm). C Schematic illustration of the engine construct. A 500nm-diameter particle is tethered to the distal end of the fourth 6HB bundle, allowing optical tracking of switching events. The first 6HB is equipped with 53 single-stranded sticky ends, which can hybridize with a substrate functionalized with BSA–biotin, streptavidin, and biotin–DNA (see Supplementary Figs. 1 and 13 for details). RNA hybridization shifts the engine into the folded state; RNase H cuts the RNA and resets the engine to the unfolded state.